fossil fuel (a hydrocarbon deposit-petroleum, coal, or natural gas-derived from living matter of a previous geologic time and used for fuel; when burned, it releases carbon dioxide and other heat-trapping gases into the atmosphere)

Have students to sit in a large circle. Hand out an index card to every second or third student so they're evenly placed around the circle. Explain that students will create a "worldwide web" to illustrate how the terms on their cards are connected.

Hand the ball of string to a student holding a card. Ask her or him to think of one way the term on the card is connected to a term on another card. Have the student explain the connection and then, holding onto the string, pass the ball to that student. The next student should do the same thing. Continue this activity until all terms have been connected and the web is visible. (Several cards will be used more than once.)

Ask students who do not have cards to describe connections that weren't included in the web.

Students may make these connections:

SUVs and other cars burn fossil fuels, which release carbon dioxide into the atmosphere. Carbon dioxide contributes to global warming because it is a gas that traps heat in the atmosphere. Global warming is causing the Arctic sea ice to melt. The melting sea ice releases freshwater into the Gulf Stream. This would slow down the Gulf Stream, affecting the climate in Western Europe.

Global warming is decreasing the amount of sea ice. With less sea ice, when the wind blows, ocean waves become much larger. Larger waves contribute to coastline erosion because they travel farther ashore and have more energy.

Increased temperatures brought by global warming cause glaciers to melt. Water from the glaciers is added to ocean water, causing sea levels to rise. Ocean levels are also expanding because as global warming heats the water, it expands. Rising sea levels contribute to coastline erosion.

Global warming is causing sea ice to form later in the fall and melt earlier in the spring. This threatens the survival of polar bears that depend on the ice to hunt seals, their primary food source, because they have fewer weeks of feeding.

After this activity, ask students to write a paragraph explaining the following sentence: The Arctic is part of a larger climate system. They should use at least three supporting details in their paragraph.

EvaluationUse the following three-point rubric to evaluate students' work during this lesson.

Three points:Students were active in class discussions; showed strong understanding of concepts; made at least one strong, clear connection between the terms; completed a thorough, thoughtful paragraph that included at least three supporting details.

Two points:Students participated in class discussions; showed satisfactory understanding of concepts; made one acceptable connection between the terms; completed an adequate paragraph that included two or three supporting details.

One point:Students participated minimally in class discussions; showed minimal understanding of concepts; did not make acceptable connections between the terms; created an incomplete paragraph with one or no supporting details.

VocabularyArcticDefinition:Region around the North Pole, including the Arctic Ocean and parts of North America, Asia, and EuropeContext:Global warming has had a devastating impact on the Arctic's geography and wildlife.

fossil fuelDefinition:A hydrocarbon deposit-petroleum, coal, or natural gas-derived from living matter of a previous geologic time and used for fuelContext:When burned, fossil fuels release carbon dioxide and other heat-trapping gases into the atmosphere.

global warmingDefinition:Gradual increase of the temperature of Earth's lower atmosphereContext:Many scientists believe that global warming is caused by an increase of heat-trapping gases like carbon dioxide in the atmosphere.

Gulf StreamDefinition:Major current in the Atlantic Ocean that carries warm water from the Gulf of Mexico up the coast of North America and toward EuropeContext:As it flows, the Gulf Stream releases heat into the northern hemisphere.

permafrostDefinition:Soil or rock in polar regions that remains frozen year-roundContext:Global warming is causing some permafrost to melt and erode coastlines.

sea iceDefinition:A layer of ice formed from seawater; it changes with seasons and floats on the ocean, carried by winds and currentsContext:The thickness of sea ice varies, but on average it's about three meters thick.

StandardsScienceThe National Science Education Standards provide guidelines for teaching science as well as a coherent vision of what it means to be scientifically literate for students in grades K-12. To view the standards, visithttp://books.nap.edu.

This lesson plan addresses the following national standards:

Science in Personal and Social Perspectives: Populations, resources and environments; Science and technology in society

Life Science: Populations and ecosystems; Diversity and adaptations of organisms

Physical Science: Properties and changes of properties in matter

Social StudiesThe National Council for the Social Studies (NCSS) has developed national standards to provide guidelines for teaching social studies. To become a member of the NCSS, or to view the standards online, go tohttp://www.socialstudies.org.